By now the world knows that Hillary Clinton won the Democratic primary in New Hampshire despite polls taken only a day or two before that showed Barack Obama with a significant lead, ranging from 7 to 13%. Hillary won with 39% of the Democratic vote while Obama won 37%.
How to explain the dramatic turnaround? Not surprisingly, pundits, including the very same individuals who expressed confidence immediately before the vote that Obama would triumph, have offered many “explanations.” These range from poor sampling by pollsters, to an unanticipated turnout by female voters who voted strongly for Hillary, to last minute changes by voters affected by Hillary’s emotional moment the day before the vote, to the “Bradley effect.”
What exactly is the “Bradley effect?” Wikipedia, not always the most reliable source for accurate information, describes it as following:
The term Bradley effect or Wilder effect refers to a phenomenon which has led to inaccurate voter opinion polls in some American political campaigns between a white candidate and a non-white candidate. Specifically, there have been instances in which statistically significant numbers of white voters tell pollsters in advance of an election that they are either genuinely undecided, or likely to vote for the non-white candidate, but those voters exhibit a different behavior when actually casting their ballots. White voters who said that they were undecided break in statistically large numbers toward the white candidate, and many of the white voters who said that they were likely to vote for the non-white candidate ultimately cast their ballot for the white candidate. This reluctance to give accurate polling answers has sometimes extended to post-election exit polls as well.
Researchers who have studied the issue theorize that some white voters give inaccurate responses to polling questions because of a fear that they might appear to others to be racially prejudiced. Some research has suggested that the race of the pollster conducting the interview may factor into that concern. At least one prominent researcher has suggested that with regard to pre-election polls, the discrepancy can be traced in part by the polls' failure to account for general conservative political leanings among late-deciding voters.
Bill Schneider, CNN’s senior political analyst, suggests there is no empirical support for the Bradley effect in the New Hampshire primary. He indicates that the pre-vote polls generally gave Obama 37% of the Democratic vote and Clinton 30%. In other words, Obama won roughly the same percentage of the vote that the pre-vote polls had suggested he would. The change was that Hillary moved from 30% to 39%. Anderson Cooper, CNN’s current ‘star,’ had Schneider on his program this evening (Jan 9, 08) to set forth these statistics but then introduced a guest who asserted that, while he had no empirical evidence on the issue, he thought the Bradley effect certainly might have operated. How unpersuasive that bit of rank speculation was.
Further, while I have not read studies on the Bradley effect, I think there is another important difference between the New Hampshire primary and the elections in which the Bradley effect allegedly has operated. This was a primary, not a general election.
As stated in Wikipedia, “Researchers who have studied the issue theorize that some white voters give inaccurate responses to polling questions because of a fear that they might appear to others to be racially prejudiced.” That might make sense in a general election, such as the Bradley-Deukmejian contest, where traditionally Democratic voters are polled and fear that indicating a preference for the Republican despite their history of voting Democratic and/or for liberal candidates might suggest they are racially prejudiced. But this was a primary where there were three liberal Democratic candidates vying for voter support, Obama, Clinton and John Edwards. A liberal Democrat who harbored racial animus toward Obama had no need to tell a pollster he or she favored Obama. The voter could just as easily have stated a preference for Clinton or Edwards without appearing to be racially prejudiced. By stating a preference for Clinton or Edwards, the voter would not have been abandoning a past liberal or Democratic voting record or even expressing a preference for a more conservative candidate. Indeed, John Edwards was advocating a program to the left of Obama and Clinton.
In other words, it appears that neither the statistics nor the underlying rationale that have in other elections supported an argument that there was a Bradley effect were present in the New Hampshire Democratic primary in 2008.
